When using a cabinet having several drawers, there is always a risk of tipping the cabinet if more than one loaded drawer is opened at the same time. It then becomes desirable to provide the cabinet with a mechanism preventing the simultaneous opening of several drawers. There are currently many different mechanisms on the market proposed for accomplishing this function.
Examples of such mechanisms can be found in U.S. patent Nos. U.S. Pat. No. 3,404,929 (Wright et al.), U.S. Pat. No. 4,396,239 (Wissman), U.S. Pat. No. 4,425,013 (Killen), U.S. Pat. No. 4,838,624 (Walla) and U.S. Pat. No. 6,238,024 (Sawatzky), showing various models of interlocking or anti-tip systems for cabinets.
One of the existing problems in many of the proposed mechanisms is that, even though it is not possible to open a second drawer when one drawer is already opened, it is still possible to open multiple drawers if they are all opened at the same time. Also, many mechanisms are large and take a lot of space at the cost of the space for the drawers and thus the space available for storage of articles (i.e. reduced ratio of drawer size with respect to cabinet size).
Many mechanisms are difficult to install and also to reconfigure when such a possibility exists for changing the drawer positions. Tools are usually required for achieving such operations.
Another problem occurs during preparation of the cabinet. Indeed, when time comes to place all the drawers in the cabinet, it is necessary to perform a manual reset of the mechanism after having inserted each drawer to enable insertion of a second one, and then a third one, etc. This extends the assembly times and represents a certain difficulty when inserting the last drawers when they are deep and little high. Indeed, it becomes then complex to reactivate the mechanism because of the constricted space left by the missing drawer. Furthermore, when this operation is achieved on the spot following a reconfiguration and by a user not knowing much how the mechanism operates, the user who does not understand that the mechanism must be reactivated after insertion of each drawer will fail to insert the second drawer. The user is then likely to abruptly force the second drawer to close, thereby breaking the pieces of the mechanism.
A frequent problem in the proposed mechanisms is that they do not tolerate lateral or vertical variations in the positions of the operating pieces, which causes malfunction of the mechanisms.
A further problem with many of the proposed mechanisms is that they are often sensible to vibrations which may cause undesired release of the drawers.
In addition, a separate device must often be provided to lock all the drawers e.g. for safekeeping valuable articles stored in the cabinet.